Calc element and JOIN TABLE in the list

[tadzio]

I have a list without saving records. only ID and date_time
To this list I joined table RIGHT JOIN.
I would like to use a calc element to display an item from an JOINed table.
For example:

Ajax observe fields
{joined_table_element___track_date}

Calculation: return ("{joined_table_element___track_date_raw}");

Is it possible? Do I have to do it in the main list only?